For 3.7.1 a non-admin trying to "Add Media" results in the ajax-admin call constantly repeating the call to query-attachments with the same parameters. The response seems legit though, firebug shows the same json. The net log just shows an infinite number of calls to admin-ajax.
If the user is admin the admin-ajax call correctly increments the [paged] parameter each time, in my case returning 3 screens worth.
I think this was working in 3.6 and it's more likely a WP issue than this plugin but I have to start here.
Also I have code changes that allow updating of a user-submitted post if you are interested when I get this working again.